Since we got TD 5.2 after 5.1, we face a a critical problem as follows:

The application we are developing is based on a central/main mdi form and
the rest of the forms are called to be created inside the mdi.
If for any reason the user will change the focus from the application to
other windows xp (latest service pack) program (i.e. notepad) and then
return back,
then for some reason the mdi gets a white lane from top to bottom of the
screen (when mdi is maximized only) - 3to5 cm width by the application
height.
It looks more like a bug rather than a mistake in the code. We tried to put
code in to the Activate message of the mdi form so that to set the size of
the mdi manually, but nothing.

The white lane/box dissappears right after you will call a dialog and close
it or when changing from maximized state to normal (for the mdi form).